Polysaccharides possess various biological activities that can be applied in food, pharmaceutical, cosmeceutical, textile and paper industries. Although industrial polysaccharides are mainly produced by higher plant and seaweed, microorganisms are recognized as potential substitutes for the current major resources of polysaccharides due to their easy purification process and high production efficiency. In this study, we explored extracellular polysaccharides (EPS) produced by the fungus Gibellulopsis serrae strain JJ-W1 isolated from seawater. When cultured in media supplemented with three different carbon sources including glucose, maltose, and sucrose, the highest EPS production was observed in the glucose medium. In addition, the G. serrae EPSs showed inhibitory effects on collagenase activity. At a concentration of 20 mg/mL, collagenase activity was completely inhibited by the G. serrae EPSs, and the half-maximal inhibitory concentration(IC50) value was 6.21 ± 0.26 mg/mL. Based on the structural analysis of FT-IR spectra, the G. serrae EPSs exhibited different properties depending on the carbon sources. The EPSs produced in the glucose medium contained both α- and β-glycosidic linkages, whereas those from maltose or sucrose media contain only α-glycosidic bonds. Given the limited research on fungal polysaccharides and their collagenase inhibition, this study may provide basic information for their potential use in cosmetics.

Marine macroalgae are important in coastal ecosystems and interact with marine microorganisms. In this study, we isolated fungi from seven types of marine macroalgae including Cladophora sp., Gloiopeltis furcate, Gracilariopsis chorda, Hydroclathrus clathratus, Prionitis crispata, Sargassum micracanthum, and Ulva lactuca collected in Korea. Morphological and phylogenetic analyses identified the isolates as four Aspergillus spp. (A. fumigatus, A. sydowii, A. tamarii, and A. terreus), three Penicillium spp. (P. crustosum, P. jejuense, and P. rubens), and Cladosporium tenuissimum. Among them, A. fumigatus TOPU2, A. tamarii SH-Sw5, and A. terreus GJ-Gf2 strains showed the activities of all enzymes examined (amylase, chitinase, lipase, and protease). Based on the enzymatic index (EI) values in solid media, A. terreus GJ-Gf2 and C. tenuissimum UL-Pr1 exhibited the highest amylase and lipase activities, respectively. Chitinolytic activity was only observed in A. terreus GJ-Gf2, A. tamarii SH-Sw5, and A. fumigatus TOP-U2. Penicillium crustosum ULCl2 and C. tenuissimum UL-Pr1 showed the highest protease activities. To the best of our knowledge, this is the first report of lipolytic and proteolytic activities in a marine-derived C. tenuissimum strain. Overall, the fungal strains isolated from the marine macroalgae in this study actively produced industrially important enzymes.